The present invention relates to waveform displays on a measurement instrument, and more particularly to a method of easily indicating and manipulating a zoom region of a waveform on a display.
When zooming on waveforms in a measurement instrument with large zoom scale factors, it is often difficult to identify which region of a displayed waveform is being zoomed. Also when the zoom scale factors become extremely large, manipulation of zoom regions becomes very difficult as the indication of the zoom region on the displayed waveform becomes very small. When multiple regions of the displayed waveform are zoomed simultaneously, the difficulty of identifying and manipulating the unique zoom regions is compounded.
In order to look at particular portions of a long data record representing the displayed waveform acquired by the measurement instrument, such as a digital storage oscilloscope, in order to see details about the displayed waveform, regions within the long data record are selected by a zoom function. These zoom regions of the displayed waveform have previously been indicated by drawing a zoom box with the displayed waveform represented by the long data record, or by displaying the zoom regions as different colors within the displayed waveform, also referred to as shading. When the zoom region for the displayed waveform becomes smaller than two or three pixels on a display, i.e., appear essentially as a very narrow vertical line that may be lost in the displayed waveform, these regions are difficult to quickly identify and very difficult to manipulate except via conventional knobs.
Zoom regions also have been indicated via a summary view that uses a single line representing the displayed waveform with paired square brackets on the line to indicate which portion of the displayed waveform is being displayed on a zoomed waveform view. Vertical bars and a dashed line represent the displayed waveform and the square brackets indicate on the dashed line the region of the displayed waveform currently being displayed in the zoomed waveform view.
Horizontal manipulation of the zoom region position is typically accomplished through the use of knobs. Use of knobs does not easily allow the zoom region to move in large increments in either direction, i.e., using knobs to move the zoom region to a different portion relatively distant from the original portion is slow.
What is desired is a method of easily indicating and manipulating a zoom region of a waveform being displayed.